Hello and welcome. I have been modding The Sims 4 for a few years now. Below are sites currently hosting my mods. Not all mods are on all sites. I don't place my content behind pay walls, and I respectfully ask that you do not as well.
Sites where I have uploaded my content:
Nexusmods.com is a multi-game file hosting site for content creators and comes complete with its own well-developed content download manager called Vortex (not necessary for Sims4 content).
This is by far my favorite hosting site, in that it gives a broader at-a-glance look of all the uploads, and content creators enjoy immense latitude over the way they wish to portray their work. Nexusmods.com does not enjoy nearly the traffic of some other sites, but it's been around since 2011 and its content posting automation is straight forward and an absolute breeze to update content and maintain version control.
If you want a lot of Sims4 enthusiasts to see your creations, this well-trafficked site is an excellent place to host your files.
If your creations are rated G, you have patience with high levels of moderation, and really want a large number of people to see your creations, then I recommend this site.
Sims4Studio.com, in addition to providing Sims4Studio, which is an excellent tool which many content creators rely on, has a rudimentary showcasing feature, its major drawback being that the site does not host user content, so all images and files must be uploaded elsewhere and then linked to a user's "studio." All of my content appearing on Sims4Studio, for example, link to SimsFileShare and imgur.
If you are content creator, I highly recommend visiting Sims4Studio.com to download its studio tool, but recommend finding a true file-hosting site such as modthesims.info or nexusmods.com to showcase your content.